Equivalent Feet of Straight Pipe

When modeling a piping system, sometimes it is easier to model the entire system as a straight pipe and apply the flow equations to the pipe length.  The table below is what the equivalent straight line pipe can be used.  To use these, sum the amount of horizontal pipe plus the total equivalent length of sum of the fittings.  This will give you a reasonable approximation of the expected pressure drop through the pipe.  For more precise solutions, a flow modeling program should be used.

 

Equivalent Feet of Straight Pipe
Pipe Size	Inside Dia	Gate or Ball Fully Open	90° Elbow	Long Rad 90° or 45° Std Elbow	Std Tee - Thru Flow	Std Tee Branch Flow	Close Return Bend	Angle Valve Full open	Globe Valve Full open	Butterfly Valve	90° Weld Elbow		Mitre Bend		Swing Check
											r/d = 1	r/d = 2	45°	90°
1/2	0.622	0.41	1.55	0.83	1.04	3.11	2.59	7.78	17.6						5.18
3/4	0.824	0.55	2.06	1.1	1.37	4.12	3.43	10.3	23.3						6.86
1	1.049	0.7	2.62	1.4	1.75	5.25	4.37	13.1	29.7						8.74
1 1/4	1.38	0.92	3.45	1.84	2.3	6.9	5.75	17.3	39.1						11.5
1 1/2	1.61	1.07	4.03	2.15	2.68	8.05	6.71	20.1	45.6						13.4
2	2.067	1.38	5.17	2.76	3.45	10.3	8.61	25.8	58.6	7.75	3.45	2.07	2.58	10.3	17.2
2 1/2	2.469	1.65	6.17	3.29	4.12	12.3	10.3	30.9	70	9.26	4.12	2.47	3.08	12.3	20.6
3	3.068	2.04	7.67	4.09	5.11	15.3	12.8	38.4	86.9	11.5	5.11	3.07	3.84	15.3	25.5
4	4.026	2.68	10.1	5.37	6.71	20.1	16.8	50.3	114	15.1	6.71	4.03	5.03	20.1	33.6
5	5.047	3.36	12.6	6.73	8.41	25.2	21	63.1	143	18.9	8.41	5.05	6.31	25.2	42.1
6	6.065	4.04	15.2	8.09	10.1	30.3	25.3	75.8	172	22.7	10.1	6.07	7.58	30.3	50.5
8	7.981	5.32	20	10.6	13.3	39.9	33.3	99.8	226	29.9	13.3	7.98	9.98	39.9	33.3
10	10.02	6.68	25.1	13.4	16.7	50.1	41.8	125	284	29.2	16.7	10	12.5	50.1	41.8
12	11.938	7.96	29.8	15.9	19.9	59.7	49.7	149	338	34.8	19.9	11.9	14.9	59.7	49.7
14	13.124	8.75	32.8	17.5	21.8	65.6	54.7	164	372	38.3	21.8	13.1	16.4	65.6	54.7
16	15	10	37.5	20	25	75	62.5	188	425	31.1	25	15	18.8	75	62.5
18	16.876	16.9	42.2	22.5	28.1	84.4	70.3	210	478	35.2	28.1	16.9	21.1	84.4	70.3
20	18.814	12.5	47	25.1	31.4	94.1	78.4	235	533	39.2	31.4	18.8	23.5	94.1	78.4
24	22.628	15.1	56.6	30.2	37.7	113	94.3	283	641	47.1	37.7	22.6	28.3	113	94.3
30	28	18.7	70	37.3	46.7	140					46.7	28	35	140
36	34	22.7	85	45.3	56.7	170					56.7	34	43	170
42	40	26.7	100	53.3	66.7	200					66.7	40	50	200
48	46	30.7	115	61.3	76.7	230					76.7	46	58	230

     

Pipe Size	Equivalent Length in terms of small d										Entrance	Exit
	Enlargement					Contraction					└──	└──
	Sudden			Std. Reducer		Sudden			Std. Reducer		◄▬	▬►
	d/D = ¼	d/D = ½	d/D = ¾	d/D = ½	d/D = ¾	d/D = ¼	d/D = ½	d/D = ¾	d/D = ½	d/D = ¾	┌──	┌──
1/2	1.7	1.1	0.38	1.3	0.38	0.9	0.63	0.38	0.38		1	2
3/4	2.5	1.5	0.51	1.7	0.51	1.3	0.9	0.51	0.51		1.5	2.8
1	3.2	2	0.7	2.3	0.7	1.8	1.3	0.7	0.7		2	4
1 1/4	4.8	3	1	3.3	1	2.2	1.8	1	1		2.7	5.5
1 1/2	5	3	1	4	1	3	2.2	1	1		3.3	6.8
2	7	4	1	5	1	3	3	1	1		4.5	9
2 1/2	8	5	2	6	2	4	3	2	2		5.5	11
3	10	6	2	8	2	5	4	2	2		9	18
4	12	8	3	10	3	6	5	3	3		10	20
6	18	12	4	14	4	9	7	4	4	1	17	33
8	25	16	5	19	5	12	9	5	5	2	23	46
10	31	20	7	24	7	15	12	6	6	2	30	60
12	37	24	8	28	8	18	14	7	7	2	40	80
14	42	26	9			20	16	8			42	84
16	47	30	10			24	18	9			50	100
18	53	35	11			26	20	10			60	120
20	60	38	13			30	23	11			70	1470
22	65	42	14			32	25	12			80	160
24	70	46	15			35	27	13			90	180